During a recent discussion, a manager related to me that their most common defects are shorts, sinks, and flash. She then stated that this is inherent to the molding process could not really be changed.
Shorts, Sinks, & Flash: Whenever these three are the top defects at a facility, it is because the molds are being filled too much during 1st Stage Fill. When the mold fills too much during first stage fill, the packing pressure is primarily used to ensure gate seal since the mold cavity is full. This only works when the material viscosity is identical to the time the process was established. When the viscosity drops, the mold will flash, when the viscosity rises, the mold will short or sink.
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